Inside Jason Prado's South of Market loft last weekend, the Facebook engineer and many of his tech industry friends spent the day spray painting picket signs.

They were preparing to protest Palantir, a secretive data analysis company launched with seed money from the CIA and cofounded by tech billionaire Peter Thiel, President-elect Donald Trump's tech adviser. Mr. Prado had never led a protest before, he says, but felt compelled after hearing reports about Palantir’s ties to federal immigration agencies involved with deportations.

Now, Prado and many of his fellow Silicon Valley denizens worry that Palantir’s close ties to the incoming Trump administration could become the building blocks for a Big Brother-like firm that deploys its technology to track and surveil American citizens.

"It’s time to turn an eye inward and think critically about tech’s role in the world," he says. "I truly believe that tech is a force for good in this world, and large companies are especially so."

Silicon Valley has long been an apolitical bastion of brainy engineers, entrepreneurs, and venture capitalists more concerned about the next hot social media startup than what's happening in Washington. That began changing as internet access spread and companies such as Facebook and Apple become indelibly linked to daily life – and to politics.

As a result, Apple, Google, and Facebook hired lobbyists in Washington and boosted political spending. Technologists have become more socially active as encryption, online censorship, internet surveillance, and digital security have become politicized.

Now, as Trump is set to take office after an election in which Russian hackers, internet trolls, and fake news all played a role, Silicon Valley is reassessing its place in the national political conversation and pockets of tech workers are beginning to speak out with a more forceful – and unified – voice.

"Tech people used to be very status quo because the status quo was working great for tech," Prado says. "We took our eyes off the government’s wheels for a while and the government’s gone awry. I think people are interested in the government’s affairs for the first time in a long time."

That interest is materializing in campaigns such as dobetter.tech, which Prado and his friends launched to draw attention to Palantir's close ties to Trump. Specifically, they're worried that the firm could aid the development of a Muslim registry, an idea that surfaced during the election.

A separate petition called neveragain.tech also circulated through the tech community, asking workers to never aid in building a Muslim registry. More than 2,800 people – including three who say they work at Palantir – signed the pledge.

Assurances from the Trump camp, and from many of his administration appointees, that a Muslim registry isn't in the works haven't satisfied Prado and other dobetter.tech and neveragain.tech supporters. On Wednesday, in front of Palantir's Palo Alto headquarters, more than 60 people gathered to demand that the company resist any effort to build such a database or use its technology to assist with deportations.

When reached for comment on the protest, Palantir responded with a one-sentence statement to Passcode: "Both our CEO and our board chair have stated that Palantir will not participate in any kind of Muslim registry."

Palantir Chief Executive Officer Alex Karp and Mr. Thiel both attended a recent summit between Trump and Silicon Valley’s most powerful leaders. Compared to other tech titans such as Apple or Alphabet (Google's parent company), both worth more than $500 billion, Palantir was by far the smallest company represented with, at its largest, a $20 billion valuation.

Prado and his colleagues started getting concerned about Palantir after reports of its work with immigration agencies such as the US Customs and Border Protection agency surfaced. Despite Palantir’s repeated public pledges to not build a Muslim registry, dobetter.tech felt Palantir was a "special case" deserving more scrutiny – especially because much of the work it does for government agencies and businesses is protected under nondisclosure agreements.

"A simple 'we would not do that' may be sufficient for some major tech companies with sensitive user data (and even there, it may not be)," dobetter.tech stated on its website. "However, when a company is already directly contracted with immigration authorities to maintain analytics systems and is already profiting from this relationship, the standards for accountability and transparency need to be higher."

One system, known as the Analytical Framework for Intelligence, collects data from federal, state, and local law-enforcement databases to create profiles of individuals from personal details, travel histories and even physical traits such as tattoos and scars. Palantir appeared to have play an important but undisclosed role in building the system, according to documents obtained by the civil liberties group Electronic Privacy Information Center.

"Our biggest concern about data mining and other uses of analytics is that it has the potential to entrap innocent people that has potential chilling effects," says Jay Stanley, senior policy analyst on technology at the American Civil Liberties Union. "Palantir’s tools can be turned to check for associations for that isn't explicit."

As an apparent check on its own growing data mining and surveillance technology, Palantir created the Palantir Council of Advisers on Privacy and Civil Liberties (PCAP) in 2012. Composed of top academics on the issues of privacy law, little is still known about the role of the council. It was unknown if the council was even active.

When asked by Passcode, UC Berkeley law professor and PCAP member Chris Hoofnagle says the council is still active and meets four times a year. “The Palantir people are devoted and hardworking, and they care about civil liberties,” Hoofnagle wrote in an email. "My experience has been rewarding."

For venture capitalists that keep Silicon Valley startups financially afloat, Palantir is seen as a mixed bag, according to David Cowan, a partner at the Palo Alto-based Bessemer Ventures. With a longstanding record of working with both federal government agencies such as the CIA and local law enforcement agencies such as the Los Angeles Police Department, Palantir had a "materially positive impact on national security," according to Cowan.

But he also sees Palantir as a double-edged sword. "When master surveillance tools are redirected from foreign threats to American citizens, we just crossed over from national security to Big Brother."